U.S. patent number 7,080,710 [Application Number 10/748,433] was granted by the patent office on 2006-07-25 for wheelchair control sensor using movement of shoulders and wheelchair drive control apparatus using the same.
This patent grant is currently assigned to Korea Advanced Institute of Science and Technology. Invention is credited to Dong Soo Kwon, Kyoo Bin Lee, Soo Chul Lim, Jae Woong Min.
United States Patent |
7,080,710 |
Kwon , et al. |
July 25, 2006 |
Wheelchair control sensor using movement of shoulders and
wheelchair drive control apparatus using the same
Abstract
The present invention is a wheelchair control sensor for
controlling a powered wheelchair for spinal cord-injured persons,
who are incapable of using their hands, using movement of
shoulders. The wheelchair control sensor includes two shoulder
straps, two casings, two Force Sensitive Resistor (FSR) sensors,
pressing balls, and a waist belt. The casings each have an internal
space defined by an inclined surface. The FSR sensors are attached
to the inclined surfaces of the casings or surfaces opposite to the
inclined surfaces. The pressing balls are connected to the shoulder
straps to press the FRS sensors while being moved through the
internal spaces of the casings by external force. The waist belt is
worn on an upper garment with the two casings spaced apart from
each other at a certain interval.
Inventors: |
Kwon; Dong Soo (Daejeon,
KR), Lee; Kyoo Bin (Gangwon-do, KR), Min;
Jae Woong (Daejeon, KR), Lim; Soo Chul (Seoul,
KR) |
Assignee: |
Korea Advanced Institute of Science
and Technology (Daejeon, KR)
|
Family
ID: |
33308277 |
Appl.
No.: |
10/748,433 |
Filed: |
December 30, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040216943 A1 |
Nov 4, 2004 |
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Foreign Application Priority Data
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Mar 26, 2003 [KR] |
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10-2003-0018856 |
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Current U.S.
Class: |
180/316;
180/907 |
Current CPC
Class: |
A61G
5/04 (20130101); A61G 5/1054 (20161101); A61G
5/048 (20161101); A61G 2203/42 (20130101); A61G
2203/14 (20130101); Y10S 180/907 (20130101) |
Current International
Class: |
B62D
11/00 (20060101) |
Field of
Search: |
;180/316,907,65.1,6.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dickson; Paul N.
Assistant Examiner: Webb; Tiffany
Attorney, Agent or Firm: Graybeal Jackson Haley LLP
Claims
What is claimed is:
1. A wheelchair control sensor for controlling a powered wheelchair
for a user who is incapable of using their hands, comprising: two
casings each including an internal space having an inclined
surface; two force sensitive resistor (FSR) sensors attached to the
inclined surfaces of the casings or surfaces opposite to the
inclined surfaces; pressing balls to press the FRS sensors while
being moved through the internal spaces of the casings by external
forces; two shoulder straps for providing the external forces to
the pressing balls according to movements of a user's shoulders;
and a waist belt to be worn on an upper body of the user with the
two casings spaced apart from each other at a certain interval.
2. The wheelchair control sensor as set forth in claim 1, wherein
each of the inclined surfaces has a uniform width.
3. The wheelchair control sensor as set forth in claim 1, wherein
each of the shoulder straps is connected to the pressing ball at a
first end thereof and secured to the waist belt at a second end
thereof.
4. A wheelchair drive control apparatus for receiving a detection
signal from a wheelchair control sensor, which controls a powered
wheelchair for spinal cord-injured persons using movement of
shoulders, and controlling operation of wheels of the powered
wheelchair, the wheelchair control sensor comprising: two casings
each including an internal space having an inclined surface; two
force sensitive resistor (FSR) sensors attached to the inclined
surfaces of the casings or surfaces opposite to the inclined
surfaces; pressing balls to press the FRS sensors while being moved
through the internal spaces of the casings by external forces; two
shoulder straps for providing the external forces to the pressing
balls according to movements of a user's shoulders; and a waist
belt to be worn on an upper body of the user with the two casings
spaced apart from each other at a certain interval.
Description
This application claims priority from Korean Patent Application No.
10-2003-0018856 filed 26 Mar. 2003, which is herein incorporated by
reference.
FIELD OF THE INVENTION
The present invention relates generally to a wheelchair control
sensor for a user who are incapable of moving their hands, and more
particularly, to a wheelchair control sensor capable of controlling
a powered wheelchair using the movement of the shoulders of spinal
cord-injured persons Additionally, the present invention relates to
an apparatus that controls the operation of a wheelchair using the
wheelchair control sensor.
BACKGROUND OF THE INVENTION
Most of spinal cord-injured persons, who are incapable of moving
their hands, cannot drive wheelchairs but utilize wheelchairs with
the aid of assistants. Furthermore, it is difficult to acquire
wheelchairs equipped with control units that can be used by spine
cord-injured persons. Currently, there are few wheelchairs that can
be used by spine cord-injured persons who are incapable of moving
their hands.
For wheelchairs for handicapped persons, there have been proposed a
wheelchair that can be controlled in such a way that a contact type
or contactless type switch is mounted on a headrest and the
movement of the head of a handicapped person is measured another
type of wheelchair has a joystick mounted near the chin of a
handicapped person and the joystick is controlled by the chin.
For example, U.S. Pat. No. 4,093,037 entitled "Head actuated
control unit for battery-powered wheelchair" discloses a technique
of controlling a wheelchair through the movement of the head of a
handicapped person. A joystick is mounted on a headrest and a
handicapped person controls the joystick by moving his or her head.
Furthermore, an on/off switch is mounted on the headrest and a
wheelchair is turned on/off in case of necessity.
U.S. Pat. No. 4,260,035 entitled "Chin controller system for
powered wheelchair" discloses a technique of controlling a
wheelchair by controlling a joystick using the chin of a
handicapped person. This patent is constructed in such a way that
an angle sensor is positioned behind the neck of a handicapped
person and the angle sensor is connected to the chin of a
handicapped person with a long bar. When a handicapped person moves
his or her chin, the angle of the bar that is rotated according to
the movement of the chin is measured, and a wheelchair is
controlled according to the measured angle. For example, when a
handicapped person moves his or her chin in a vertical direction, a
wheelchair is controlled to move in forward and backward
directions. In contrast, when the handicapped person moves his or
her chin in a horizontal direction, the wheelchair is controlled to
move in a lateral direction.
Although wheelchairs using the patented techniques have been
marketed, most of handicapped persons feel uncomfortable about
putting on a special apparatus that is not used by normal persons.
Handicapped persons tend not to use wheelchairs equipped with
control units that are exposed to the views of other persons.
Further, the prior art technology is inconvenient in that
handicapped persons control joysticks by moving their chins, or
handicapped persons control joysticks mounted on headrests by
moving their heads.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a
wheelchair control sensor, which is worn on the upper body of a
spine cord-injured person who is incapable of moving his and her
hands, measures the direction and amount of the movement of the
shoulders and controls a powered wheelchair, thereby conveniently
controlling the powered wheelchair without being concerned about
its appearance.
Another object of the present invention is to provide an apparatus
for controlling the driving of a powered wheelchair, which is
capable of conveniently controlling the powered wheelchair using
the wheelchair control sensor.
In order to accomplish the above object, the present invention
provides a wheelchair control sensor for controlling a powered
wheelchair for a user who is incapable of using their hands,
comprising: two casings each including an internal space having an
inclined surface; two force sensitive resistor (FSR) sensors
attached to the inclined surfaces of the casings or surfaces
opposite to the inclined surfaces; pressing balls to press the FRS
sensors while being moved through the internal spaces of the
casings by external forces; two shoulder straps for providing the
external forces to the pressing balls according to movements of the
user's shoulders; and a waist belt worn on an upper body of the
user with the two casings spaced apart from each other at a certain
interval.
In addition, a wheelchair drive control apparatus of the present
invention is characterized by receiving a detection signal from a
wheelchair control sensor, which controls a powered wheelchair for
spinal cord-injured persons using the movement of the shoulders,
and controlling operation of wheels of the powered wheelchair.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and other advantages of the
present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
FIG. 1 is a schematic diagram illustrating spatial relationships
between a wheelchair control sensor configured to detect the
movement of the shoulders, a spine cord-injured handicapped person,
and a control unit mounted on a powered wheelchair in accordance
with the present invention;
FIGS. 2a and 2b are an exploded perspective view of the wheelchair
control sensor and a view of an assembled wheelchair control
sensor, respectively;
FIG. 3 is a see-through view showing the inside structure of the
casing of the wheelchair control sensor of FIG. 2b;
FIG. 4 is a sectional view taken along line A--A of FIG. 3, showing
the principle of the sensor of FIG. 2b;
FIG. 5 is a circuit diagram showing a principle of detecting the
resistance value of the wheelchair control sensor of the present
invention using a control unit;
FIG. 6 is a conceptual diagram illustrating the direction of the
powered wheelchair that is controlled by the wheelchair control
sensor of the present invention;
FIGS. 7a, 7b and 7c are graphs that compare a functional
relationship for converting the movement of the shoulders detected
by the wheelchair control sensor of the present invention into the
movement of a wheelchair and a conversional relationship for a
joystick; and
FIGS. 8A 8F are portions of a circuit diagram of the wheelchair
drive control apparatus using the wheelchair control sensor in
accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference now should be made to the drawings, in which the same
reference numerals are used throughout the different drawings to
designate the same or similar components.
A wheelchair control sensor using the movement of the shoulders in
accordance with a preferred embodiment of the present invention and
an apparatus for controlling the driving of a wheelchair using the
wheelchair control sensor are described in detail with reference to
the appended drawings.
FIG. 1 is a schematic diagram illustrating spatial relationships
between a wheelchair control sensor configured to detect the
movement of the shoulders, a spine cord-injured handicapped person,
and a control unit mounted on a powered wheelchair in accordance
with the present invention.
As shown in FIG. 1, a wheelchair control sensor 1 is constructed to
be worn on the upper garment of a handicapped person and detect the
movement of one or both shoulders of the handicapped person. A
control unit 30 is mounted on a powered wheelchair 20 to receive
detection signals from the wheelchair control sensor 10 in a wired
manner and control both wheels of the powered wheelchair 20. The
direction of the powered wheelchair 20 of FIG. 1 is controlled in
such a way that the control unit 30 receives the detection signals
from the wheelchair control sensor 10 and performs control.
FIG. 3 is a see-through view showing the inside structure of the
casing of the wheelchair control sensor of FIG. 2b. FIG. 4 is a
sectional view taken along line A--A of FIG. 3, showing the
principle of the sensor of FIG. 2b.
As shown in FIGS. 2a and 2b, the wheelchair control sensor 10 in
accordance with the present invention includes two casings 11 each
having an internal space 11b defined by an inclined surface 11a,
two force sensitive resistor (FSR) sensors 12 attached to the
inclined surfaces 11a of the casings 11 or surfaces opposite to the
inclined surfaces 11a, pressing balls 14 connected to shoulder
straps 13 to press the FSR sensors 12 while being moved upward and
downward through the internal spaces 11b of the casings 11 by
external force, and a waist belt 15 worn on an upper garment with
the two casings 11 spaced apart from each other at a certain
interval so that the pressing balls 14 can press the FSR sensors 12
while being moved upward and downward by the action of the shoulder
straps 13.
Each of the casings 11 has a cubic or hexahedral shape, and is
provided with the internal space 11b that has a inclined surface
11a having a uniform width and a descending inclination. The
inclined surface 11a is formed to have the descending inclination
forward top portion of the internal space 11b. Accordingly, the
part of the upper portion of the internal space 11b is narrower
than that of the lower portion of the internal space 11b. The
internal space 11b is sized so that the pressing ball 14 does not
escape from the internal space 11b through the upper end of the
internal space 11b after being inserted into therein through the
lower end of the internal space 11b.
The FSR sensor 12 may be attached to the inclined surface 11a of
the casing 11 or a surface opposite to the inclined surface 11a. A
connection line connected to an end of the FSR sensor 12 is exposed
to the outside of the casing 11 so that signals output from the FSR
sensor 12 can be input to the control unit 30. The FSR sensor 12 is
a thin film-shaped pressure sensor, and a variable sensor having
characteristics in that, as the external force exerted thereon
increases, the resistance value thereof becomes smaller. For
example, if it is assumed that force exerted thereon is F, the
resistance value R can be approximated to be "aF.sup.b." In this
case, "a" and "b" are constants related to the characteristics of
the FSR sensor 12 and an area on which the external force is
exerted, respectively.
The pressing ball 14 is constructed in the form of a sphere having
certain size and weight. A through hole 14a is formed through the
center line of the pressing ball 14, and a wire 16 is inserted into
the through hole 14a. The wire 16 is connected at one end thereof
to a stopper 17 having a diameter larger than that of the through
hole 14a and at the other end thereof to the shoulder straps 13.
Accordingly, the pressing ball 14 is moved according to the
movement of the shoulder straps 13.
Additonally, the waist belt 15 is constructed not only to connect
the two casings 11 with a certain interval (generally, narrower
than the distance of an adult's shoulders) interposed therebetween,
but also to allow the casings 11 to be worn on an upper garment.
That is, the waist belt 15 not only allows the two casings 11 to be
spaced apart from each other so as to position the two shoulder
straps on the user's shoulders, respectively, but also makes the
two casings 11 secured to the upper garment without displacement
even though there is movement in the shoulders. Accordingly, the
waist belt 15 may be constructed in various forms, provided that it
can secure the casings 11 to the upper garment without
displacement.
Each of the shoulder straps 13 is secured to a support portion at a
first end thereof so that the pressing ball 14 connected to a
second end of each shoulder strap 13 presses the FSR sensor 12
while being moved along the inclined surface 11a. For example, the
second end of each shoulder strap 13 may be provided with a clip to
allow the second end of each shoulder strap 13 to be secured to the
upper garment, or may be directly fixed to the waist belt 15, as
shown in FIGS. 2a and 2b. As described above, the shoulder straps
13 may be secured to any of various portions, provided that the
pressing balls 14 can press the FSR sensors 12 while moving along
the inclined surfaces 11a of the casings 11 according to the
movement of the shoulders.
A principle of controlling a powered wheelchair using the
wheelchair control sensor of the present invention, which is
constructed as described above, is described below.
FIG. 4 is a sectional view taken along line A--A of FIG. 3, showing
the principle of the sensor of FIG. 2b. FIG. 5 is a circuit diagram
showing a principle of detecting the resistance value of the
wheelchair control sensor of the present invention using a control
unit.
As shown in FIG. 4, when a handicapped person wearing the
wheelchair control sensor 10 of the present invention raises one or
both of his or her shoulders, one or both of the shoulder straps 13
located on one or both shoulders raised are moved and, therefore,
one or both of the pressing balls 14 press one or both of the FSR
sensors 12 while being moved through the internal spaces 11b of the
casings 11. Force equal to reaction force F.sub.2 and force equal
to reaction force F.sub.3 are exerted on each FSR sensor 12 and the
inclined surface 11a, respectively, by the action of tension
F.sub.1 exerted by the shoulder strap 13. The force exerted on the
FSR sensor 12 through the pressing ball 14 varies according to the
extent to which the shoulder is raised. Since the FSR sensor 12 is
a variable resistor, the resistance value decreases in proportion
to the magnitude of the tension F.sub.1 exerted by the shoulder
strap 13.
In the wheelchair control sensor 10 of the present invention, the
FSR sensors 12 are positioned in the two casings 11, respectively,
and the resistance values of the FSR sensors 12 vary according to
the magnitude of tensions F1 exerted on the FSR sensors 12 (that
is, the extent to which the shoulders are raised), thus being
capable of controlling the direction of the powered wheelchair
using the resistance values.
The resistance values of the FSR sensors 12 are transmitted to the
control unit 30 through a voltage divider. As illustrated in FIG.
5, a fixed resistor is grounded, and Vcc of 5 V is applied to the
FSR sensor 12. In this case, when weak force is applied to the FSR
sensor 12, the resistance value of the FSR sensor 12 becomes larger
and, thus, low voltage is transmitted to the Analog to Digital (AD)
converter. In contrast, when strong force is applied to the FSR
sensor 12, the resistance value of the FSR sensor 12 becomes
smaller and, thus, high voltage is transmitted to the control unit
30. The control unit 30 controls the direction of the powered
wheelchair according to the transmitted signal.
The direction of the powered wheelchair that is controlled by the
wheelchair control sensor of the present invention is described
below.
FIG. 6 is a conceptual diagram illustrating the direction of the
powered wheelchair that is controlled by the wheelchair control
sensor of the present invention. As shown in FIG. 6, the wheelchair
is operated according to the movement of a handicapped person
wearing the wheelchair control sensor 10 of the present invention,
as described below. The wheelchair turns to the left when the
handicapped person raises the right shoulder, turns to the right
when the handicapped person raises the left shoulder, moves forward
when the handicapped person raises both shoulders, and stops or
remains stopped when the handicapped person lowers both shoulders.
This operational principle is determined based on the phenomenon in
which, when a driver rotates the steering wheel of a car, the right
shoulder of the driver is raised at the time of turning to the
left, and the left shoulder of the driver is raised at the time of
turning to the right.
Furthermore, the wheelchair of the present invention moves backward
when both shoulders are quickly raised two times. In accordance
with the present invention, turning and forward movement can be
performed at the same time. For example, when the left shoulder is
fully raised and the right shoulder is half raised, the wheelchair
moves forward while turning to the right.
FIGS. 7a, 7b and 7c are graphs that compare a functional
relationship for converting the movement of shoulders detected by
the wheelchair control sensor of the present invention into the
movement of a wheelchair and a conversional relationship for a
joystick. FIG. 7a is a graph showing the functional relationship
for converting the movement of shoulders detected by the wheelchair
control sensor of the present invention into the movement of a
wheelchair, in which the X-axis thereof represents the extent to
which a left shoulder is raised and the Y-axis thereof represents
the extent to which a right shoulder is raised. FIG. 7b is a graph
representing the movement of shoulders detected by the wheelchair
control sensor of the present invention in movement of a powered
wheel chair, in which the X-axis thereof represents the velocity of
the left wheel of the powered wheelchair and the Y-axis thereof
represents the velocity of the right wheel of the powered
wheelchair. FIG. 7c is a graph showing the movement of a wheelchair
according to the manipulation of a conventional joystick.
As represented by line 1 and 2 in FIGS. 7a and 7b, when both
shoulders are raised at the same time, the wheelchair moves
forward. The higher the shoulders are raised, the faster the
wheelchair moves.
In case of a joystik, as shown in the graph of FIG. 7c, as a
joystick is pushed along a Y-axis (that is, line 1), a wheelchair
moves forward, and the velocity of the forwarding movement of the
wheelchair is determined according to the extent to which the
joystick is pushed.
Line 1 and 2 of FIGS. 7a and 7b represents the case where a left
shoulder is raised while a right shoulder is kept still. In this
case, a powered wheelchair turns to the right. To make a right
turn, the left wheel of the wheelchair has to rotate forward and
the right wheel has to rotate backward and, therefore, a curve is
formed so that an X-axis value increases and a Y-axis value
decreases.
In case of a joystick, as shown in the graph of FIG. 7c, as a
joystick is pulled in the positive direction of an X-axis (that is,
line 2), a wheelchair turns to the right, and the velocity of the
right turning of the wheelchair is determined according to the
extent to which the joystick is pulled.
As described above, the present invention exploits the operational
principle of the joystick. The horizontal movement of the joystick
controls the angular velocity of the powered wheelchair and the
vertical movement of the joystick controls the forward velocity of
the powered wheelchair, so that the following Equations 1 and 2 can
be set up. Jx=Sleft-Sright (1) Jy=Sleft*Sright (2)
In the above-described Equations 1 and 2, Jx represents the
horizontal coordinates of a joystick, Jy represents the vertical
coordinates of a joystick, Sleft represents the extent to which a
left shoulder is raised, and Sright represents the extent to which
a right shoulder is raised. Each of the parameters is standardized
between 0 and 1. Since in the present invention, the movement of
the shoulder is standardized between 0 and 1, a signal for moving
the powered wheelchair backward cannot be generated. Accordingly,
when the powered wheelchair needs to move backward, a method in
which a mode is changed by quickly raising both shoulders two times
may be used to generate the signal for moving the powered
wheelchair backward.
The apparatus for controlling the driving of a powered wheelchair
using the wheelchair control sensor constructed as described above
is described below.
FIGS. 8A 8F are portions of a circuit diagram of the wheelchair
drive control apparatus using the wheelchair control sensor in
accordance with the present invention. As shown in FIGS. 8A 8f, the
wheelchair drive control unit 30 of the present invention is
constructed the same as a conventional wheelchair drive control
unit except that a powered wheelchair is controlled according to a
detection signal input from the wheelchair control sensor 10,
instead of a signal input by the manipulation of a joystick. In the
wheelchair drive control unit 30 of the present invention, the
input signal used to control the powered wheelchair is generated
based on the directions in which and the extent to which the FSR
sensors 12 are pressed.
The wheelchair drive control apparatus 30 of the present invention
includes a FSR signal input unit 31 for inputting the resistance
values of the FSR sensors 12 of the wheelchair control sensor 10
through a voltage divider, a microcontroller 32 for analyzing the
FSR signals input from the FSR signal input unit 31 using a defined
algorithm and generating an appropriate wheelchair drive control
signal, and a wheelchair interface unit 33 for converting the
wheelchair drive control signal generated by the microcontroller 32
into a signal suitable for the control specifications of the
powered wheelchair. The wheelchair drive control apparatus 30 of
the present invention further includes a signal display unit 34
comprised of a light emitting diode (LED) panel for allowing a user
to identify signals transmitted to the powered wheelchair, and a
control computer interface unit 35 for providing an interface for
the use of a control computer to supplement the function of the
microcontroller 32. The wheelchair drive control apparatus 30 of
the present invention further includes a wheel drive unit 36 for
driving the wheels of the powered wheelchair according to the
wheelchair drive control signal, a power supply unit 37 for
supplying power, and an emergency stop switch unit 38 for stopping
the wheelchair in case of emergency.
The wheelchair drive control apparatus 30 of the present invention
constructed as described above controls the powered wheelchair
using a signal input from the wheelchair control sensor 10 and the
above-described component elements in the same manner as the
conventional wheelchair drive control apparatus.
As described above, in accordance with the present invention, a
wheelchair control sensor is worn on the upper garment of a spine
cord-injured person who is incapable of moving his and her hands,
measures the direction and amount of the movement of shoulders and
controls a powered wheelchair, so that the injured person
conveniently controls the powered wheelchair without being
concerned about its appearance.
Although the preferred embodiments of the present invention have
been disclosed for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *